As someone who recently discovered and fell in love with Rhynos, I have been asking myself the same question. I started w/ two DX Rhynos and then bought a gummier Champ Rhyno and traded for another Champ Rhyno, a little bit stiffer. I love the Champion plastic ones for driving off the tee on short holes and short mid-range shots, especially at my home course which is heavily wooded. The DX ones are my go-tos for putting b/c they feel much better in the hand, but they are so damn HARD! I really, really wish I had 50-70 bucks to drop on an SE Rhyno b/c from what I understand, that's where it's at when it comes to Rhynos...great feel/grip and soft so as to not bounce out of the basket.

When the Soft Rhyno came out in the late '90s, I loved them, adopted it as my main putter, and bought ten for practice. Still have 'em. Two in very worn condition (they were the ones I carried with me and used for all putting from 1999-2006 or so), the rest have their stamps clearly visible and about two of them are in fairly good shape.